Back To Basics - Exposure: The Great Balancing Act - 5 of 5

Putting it All Together

So far, we've seen that shutter speed, aperture, and sensitivity all serve as tools to manage the amount of light we capture and modify how the camera interprets what it represents. We've seen that each tool comes with its own by-product as well. Adjusting shutter speed increases and decreases the amount of motion blur seen in our images. Adjusting aperture varies the depth of field, that is, the amount of our scene in front of and behind our subject that is in focus. And finally, adjusting sensitivity (a.k.a. ISO) shifts the scale of how light is recorded by the camera, while at the same time increasing and decreasing the amount of graininess (noise) seen in our images. With practice, the full range of each of these modifications will become a more and more natural part of your photographic decision making process - that is what I consider, The Great Balancing Act.

The Great Balancing Act

As I have echoed over and over again in this series, I don't believe there is a "proper" exposure. This is, in my opinion, in the eye of the photographer. However, I will conclude this series with a discussion of some example scenarios, where one might balance the tools at our disposal to achieve a certain result.

Scenario #1: The Baseball Game

It's a warm, summer afternoon and the home team is down by two runs in the bottom of the ninth. Two runners are on base, and the winning run is up to bat. You've got your telephoto lens on, filling your viewfinder with the batter - your goal is to stop the winning home run ball just as it leaves the bat of of the new hometown hero.

Quickly you consider that a baseball, just after the impact of a major league slugger, is traveling well over 100 MPH. The sun is providing all the light you could ever wish for, and you want as sharp a picture as you can take. What to do? We balance the tools at our disposal - With this much light, sensitivity can be set low, minimizing the noise in our shot, our aperture can be set in the mid-range, providing a medium depth of field - plenty enough to keep the batter in focus. Our primary tool of interest, hopefully clear by now is - shutter speed - we speed the shutter to it fastest rate... and <snap> we've stopped a baseball in mid air. You can still hear the crowd scream when you look at the photograph.

The key in this scenario and any photographic scenario is quickly determining what your goal is for the shot. Usually, by identifying a goal, you are pointed in the direction of which setting to optimize.

Scenario #2: The Wedding Ceremony

Before we continue down this path, let me give one small word of caution. Owning a nice SLR or dSLR does not make you a wedding photographer. Any wedding is the equivalent of the Super Bowl for any photographer, even a seasoned pro, and I want to make sure I'm not sending anyone out into the big game by giving the following example.

The bride and groom have exchanged vows and are standing there gazing at each other with all the joy and amazement that comes on such a special day. You've opened the aperture up all the way for a nice shallow depth of field, ready to really catch the moment. Your shutter speed in this light is just barely fast enough for you to be able to hold the camera still enough to take a shot without blur when - quite suddenly - the sun, coming through a few small windows in the church - goes behind a cloud. Now, with the moment quickly slipping away, you don't have enough light to make your exposure! The aperture is all the way open, no additional light to be had by changing that, and that shutter speed is already such that if you slow it down more (to let more light in) the image will be a blurry mess. What to do? Immediately, you bump up the sensitivity (ISO) and snap your image before the moment is gone - sure there's a little more noise in the image, but you were able to capture the shot. What you did was essentially made the camera more sensitive to the limited light you had, preserving your shutter speed in the process to protect from unwanted motion blur. Hopefully, at this point, you're really starting to see that knowing the ranges of each of the three variable options on the camera provides the confidence you need when you have perform the balancing act... without a net.

Scenario #3: A Child at Play

Like many photographers, some of my favorite subjects are kids at play. My three year old is a never ending source of energy, and one of the tricks to snapping a great shot of her is making sure the camera is being as flexible as possible. Let me explain. Remember the depth of field discussion from a couple days ago? It doesn't take much to realize trying to keep a kid within a 6-inch depth of field is no simple task. One of the combos I've used is bumping up the aperture to widen the depth of field, bumping up the shutter speed to stop her motion, and then raising the sensitivity to compensate for the decrease in light resulting from the other two choices. In this case, a single "most important" parameter isn't obvious - it's the combination of choices which adds flexibility to the shot, and increases the probability of catching a good pic.

 

Summary

Well, that pretty much wraps up my basic description of balancing the basic tools of the trade when in comes to exposure. As I've said before, the more you use your camera, the more comfortable you'll be at knowing what to adjust to balance the light for a perfect photograph. Just remember that aperture, shutter speed, and sensitivity each provide their own unique way of adjusting the amount of light captured by the camera, and that each comes with its own unique by-product. Future articles will address, in more exact terms the "how to" when it comes to camera hardware. For this article however, my hope was that you have found a basic understanding of the underlying mechanisms.

Please feel free to email me with questions and comments to: blog@townerjones.com

It has been a pleasure, hope you've enjoyed The Great Balancing Act.